This tip is an excerpt of the article "An exciting TCP/IP tool: File Transfer Protocol in iSeries installations" published in the September/October 2002 edition (volume 5, number 5) of the iSeries 400 Experts Journal. Provided courtesy of The 400 Group.
A key feature of FTP that you should be aware of is what is referred to as "anonymous FTP."
Anonymous FTP was created to satisfy the demand of FTP-TCP/IP users all over the Internet to send and receive files of a public domain or publicly available nature. As you can imagine, with that amount of data available for FTP transfer, it was and is simply impossible to set-up user accounts and passwords for every user on every FTP server on the Internet.
Here's how it works: When you establish a session with an FTP server, and that server asks you for your user ID, you may be allowed to enter 'anonymous' in reply. What you are trying to tell the FTP server in question is that you either (a) do not wish to identify yourself to this server (more on that in a moment), or (b) that you do not have a user account on that particular FTP server.
If the server rejects your use of 'anonymous' as a user ID, you need to contact the administrator of the FTP server in question to gain a proper user ID and password combination.
On the other hand, if after you enter 'anonymous' as your user ID, the FTP server in question replies with a request for password. This is where your personal identification comes into play.
Tradition -- and in most cases it is merely a tradition and not a session-stopping requirement -- calls for you to use your e-mail address as your password. This identifies you to the administrator of the FTP server, should they review the FTP usage history logs to see who signed-on to this FTP server.
This is not in most cases a requirement for using FTP, merely a courtesy. However, I've noticed a growing number of anonymous FTP servers which seem to scan passwords for the @ character in an effort -- weak as it may be -- to "identify" anonymous FTP users.
The iSeries, for example, presumes that the password being entered when using anonymous iSeries FTP is, in fact, a password.
On the iSeries, anonymous FTP server capabilities are put into use through the deployment of an FTP logon exit program and an FTP server request validation exit program. The use of exit programs with anonymous FTP sessions on an iSeries server serves the greater good of proper security best practices for the data on your iSeries server.
Proceed with caution
Always -- and I do mean always -- make sure that you have an active virus-checking software package running when you download files from an anonymous FTP site, unless the site is running out of the OS/400-side of an iSeries server. This is urgently true if you are using an anonymous FTP site to download files to a PC because there are lots of virus programs embedded in files available on anonymous FTP sites all over the globe -- so be careful.
About the author: Kris Neely is a senior consulting IT architect and technology relationship manager for IBM. An award-winning speaker at COMMON and other industry events worldwide, Kris has also written several books and hundreds of articles on iSeries and general IT computing.
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